html,
body {
    display: flex;

    .leftBox {
        width: 480px;
        position: relative;
        overflow: hidden;
        ul{
            position: absolute;
            top: 0;
            left: 0;
            width: 1920px;
            overflow: hidden;
            li{
                float: left;
                img {
                    width: 480px;
                    height: 753px;
                }
            }
        }

    }
    .rightBox {
        width: 1000px;
        height: 753px;
        position: relative;

        .regBox {
            position: absolute;
            top: 100px;
            left: 200px;

            .welcome {
                font-size: 44px;
                margin-bottom: 20px;
            }

            .txt {
                font-size: 28px;
                margin-bottom: 64px;
            }

            form {
                input {
                    border: 1px #aaa solid;
                    border-radius: 4px;
                    text-align: left;
                    font-size: 20px;
                    width: 438px;
                    height: 50px;
                    line-height: 50px;
                    padding: 0 20px;
                }
                .err{
                    display: block;
                    height: 30px;
                    line-height: 30px;
                    margin-bottom: 10px;
                }
                button{
                    width: 478px;
                    height: 60px;
                    text-align: center;
                    line-height: 60px;
                    font-size: 24px;
                    color: #fff;
                    background-color: #3487ff;
                    border: none;
                }
            }
        }
    }
}